Generally, a refrigerator includes a refrigerator compartment which keeps food refrigerated and a freezer compartment which keeps the food frozen. At this time, an ice machine for making ice is installed at the freezer compartment or the refrigerator compartment.
FIG. 1 is a bottom view illustrating a conventional ice machine for a refrigerator.
Referring to FIG. 1, an ice machine 10 has a heater 27 provided at a lower surface of an ice tray 11. When an ice-making is completed, the heater 27 serves to slightly melt ice strongly attached to an inner surface of the ice tray 11, thereby allowing the ice to be separated. A U-shaped sheath heater was mostly used as the heater 27.
In this case, since the heater 27 is formed to be in line contact with a lower portion of the ice tray 11 in the form of a U shape, an area which is in direct contact with the ice tray 11 is small and thus heat transfer efficiency is degraded. Much of time and electric power are consumed to transfer heat to a portion of the ice tray which is not in direct contact with the heater 27 and to melt the ice in the ice tray 11. At this time, since the ice tray 11 is excessively heated by the heater 27, a lot of time is required to cool again the ice tray 11 to an ice-making temperature in an ice-making cycle after the ice is separated, and thus an ice-making time is increased. In addition, in the conventional sheath heater, since a connection between the sheath heater and a temperature fuse which cuts off power supply when the sheath heater is overheated is complicated and a connection structure which supplies electric power to the sheath heater is also complicated, it is difficult to assemble and couple corresponding elements.